1. Field of the Invention
This invention pertains to the field of mechanics. More particularly, this invention pertains to engines that utilize gas expansion as their means of doing work. More specifically, this invention involves the application of a Stirling cycle type engine as an exemplary embodiment, but without limitation thereto. More exactly, this invention relates to a split Stirling cycle engine wherein the regenerator displacer piston and accompanying cylinder housing are distal to the compressor piston and its accompanying cylinder housing, gas volumes in each separate housing being interconnected by a hollow tube.
Mechanical work is exerted upon the engine to alternatively compress and expand a contained volume of gas. The gas contained within the engine has an ambient pressure of approximately 800 psi and is increased 20 times per second to approximately 1500 psi by a compressor piston-cylinder assembly, and is then decreased to approximately 100 psi in a sine wave fashion. The regenerator displacer piston moves from one end of its cylinder to the other end in a delayed fashion with respect to the increasing and decreasing gas pressure such that the compression gas is at its peak pressuure when the gas is at one end of the gas permeable displacer, at which point heat of compression is allowed to be rejected thereby cooling the compressed gas. Correspondingly, when the gas is expanding to its lowest pressure, the gas is at the opposite end of the gas permeable displacer, at which point heat is absorbed by the expanding gas from the surrounding environment.
Such rapidly repeated compression-expansion cycles bring about cryogenic temperatures at the expanding (cold) end of the displacer cylinder in a very short period of time.
2. Description of the Prior Art
In cooling devices of similar operation in the prior art, it was common to provide an elastic membrane or sliding flexible boot (frictional seal) to both seal the gas within the expander assembly and to delay the motion of the gas permeable regenerator displacer piston. By such means, heat build-up from the compression cycle is allowed time for rejection away from the expander assembly and during the expanding cycle, time is allowed for the expanding gas to absorb heat from the surrounding environment, thus creating a refrigerating effect upon completion of several compression expansion cycles in rapid succession.
Although satisfactory for the intended purposes, these flexible seals required careful fitting, had inherent variable drag characteristics, had limited life (mechanical failure), tended to contaminate other components, and made difficult mass production manufacturing of the expander assembly.